GATHER/SCATTER

gather/scatter (n.) the operations related to large sparse data structures. A full vector with relatively few nonzeroes is transformed into a vector with only those nonzeroes by using a gather operation. The full vector, or one with the same structure, is built from the inverse operation or scatter. The process is accomplished with an index vector, which is usually the length of the number of nonzeroes, with each component being the relative location in the full vector. See also compress/index.